Re: Ancient cellular creature over-reproduced, died by it's own gas production?

You are absolutely correct!  Some of the earliest photosynthetic life died 
from its own success and, in fact, some paleontologists refer to 
the "oxygen holocaust" as one of the single most significant extinctions 
in earth's history.  Here's what happened....

Most scientists think that, when the earth first formed, there was almost 
no free oxygen in the atmosphere.  Oxygen is fairly reactive and it'll 
combine with just about anything, so whenever oxygen appeared, it was 
immediately sucked up by things like iron (forming iron oxide, or rust), 
manganese, and other atoms or chemicals. 

About 3 billion years ago (plus or minus a few hundred million years - but 
who's counting?) photosynthesis developed.  Although the first photosynthetic
organisms probably did not release oxygen, what is called "oxygenic (or oxygen-
producing) photosynthesis" developed because it's somewhat more efficient 
than the alternatives.  Even though the early bacteria could not tolerate 
oxygen in large concentrations, it was OK that they produced it because it 
almost immediately reacted with the atoms mentioned above, so it never 
accumulated in high enough concentrations to kill the bacteria.

About 2-2.5 billion years ago, that all changed.  Around that time, most 
of the earth's crust and mantle had finished rusting, and there was 
nothing left for the oxygen to combine with.  So it started accumulating 
in the atmosphere and remained dissolved in the ocean.  Unfortunately, 
this was fatal to most of the living organisms that had produced the 
oxygen - the same chemical reactivity that led oxygen to combine so 
readily with the metals in the crust also made it toxic to organisms that 
had evolved to live in an oxygen-free environment.  Most living organisms 
on earth died from exposure to the free oxygen in the atmosphere and 
oceans.  The organisms that lived were those that lived in anoxic (oxygen-
free) pockets in the deep ocean or that could adapt to tolerate and 
(later) to use the oxygen in their biochemistry.

Interestingly, we still see signs of oxygen intolerance, even in 
modern "advanced" organisms such as ourselves.  The presence of dissolved 
oxygen in cells makes them more susceptible to the effects of exposure to 
radiation and other DNA-damaging agents, and the oxygen itself can cause 
oxidative DNA damage that can lead to problems later in life.  Oxygen can 
cause problems in lung tissues, and we can die of over-oxygenation.  So, 
even after 2 billion years, you can say that life is still learning to 
deal with the harmful effects of oxygen, even though the same chemical 
reactivity makes large organisms possible.

For more information on some of these topics, you may want to read any of 
the following books:

Oasis in Space, Preston Cloud, Norton, 1988
Planet Earth, Cesare Emiliani, Cambridge University Press, 1992
Early Life on Earth, Stefan Bengtson, Columbia University Press, 1994

There are also a number of scientific papers on this subject, varying in 
their degree of complexity.  At the risk of sounding self-congratulatory, 
I can also refer you to one I wrote that summarizes many of these in terms 
of effects on DNA damage.  It may be available through a local university 
library:

The Effects of Changing Atmospheric Oxygen Concentrations and Background 
Radiation Levels on Radiogenic DNA Damage Rates.  Karam, Leslie, and 
Anbar.  Health Physics Journal vol 81, #5, pp 545-553 (2001).